JP6362919B2 - Shape memory alloy actuation system for variable area fan nozzles - Google Patents

Description

  The present disclosure relates generally to turbofan engines, and more specifically to turbofan engines having variable area fan nozzles. Specifically, the present disclosure relates to a variable area fan nozzle including a plurality of movable petals arranged in a circumferential direction, which changes an outlet area or a throat area of the nozzle.

  Aircraft noise pollution is a serious environmental problem for communities near airports. Most of the noise generated by aircraft powered by engines during takeoff is due to the exhaust of the jet engine. Since jet engine exhaust has a relatively low frequency, noise attenuation due to jet engine exhaust is insufficient in the atmosphere alone.

  Bypass turbofan engines typically produce two types of exhaust flow components, engine core flow and fan flow. The engine core flow is discharged from the core flow nozzle after passing through the core engine. The fan flow passes through an annular passage formed by a core engine nacelle surrounding the core engine and a fan duct surrounding at least a portion of the core engine nacelle. The fan duct outlet is defined between the core nacelle and the variable area fan nozzle. In some implementations, the variable area fan nozzle is secured to the downstream end of an axially translatable reverse thrust sleeve that forms part of the fan duct. Fan flow exits from this exit. The engine flow and fan flow together create a thrust that propels the aircraft forward.

  In a bypass turbofan engine, the engine core flow throat area at the core flow nozzle and the fan flow throat area at the fan nozzle are preferably optimized for specific engine operating conditions. For example, during takeoff, a relatively high level of thrust is required for the engine as compared to the low level of thrust required during cruise flight. Increasing the amount or mass of air flow through the fan duct with a constant throat area at the fan nozzle increases the speed of the air flow. As the nozzle exit speed increases, the amount of noise produced by the nozzle increases.

  One way to increase the fan nozzle throat area as a means of reducing noise generated during high thrust events, such as during takeoff, is to use a movable flap or petal that forms a boundary with the outside of the fan nozzle outlet. is there. These flaps or petals can be displaced outwards to increase the fan nozzle throat area, thereby reducing the exhaust speed, or conversely, they can be displaced inward to increase the fan nozzle throat area. Can be reduced, thereby increasing the exhaust speed.

  The fan nozzle area is changed by deflecting a flap or panel (hereinafter referred to as “petal”) attached to the trailing edge lip region of the axially translatable reverse thrust sleeve (which reduces the fan flow) To be adjusted). As used herein (including claims), the term “sleeve” includes at least the following configurations: (1) extends from one side of the engine pylon to the opposite side along most of the circumference of the fan duct. An axially translatable piece of sleeve, (2) two axially translatable half cowls mounted on rails fixed to the upper and lower beams and extending from the upper beam to the lower beam . According to the latter configuration, the upper beam is the main hinge beam that can release the reverse thrust device to access and remove the engine. The lower beam (hereinafter referred to as “latch beam”) is a means for locking the two half cowls together. Thus, the second configuration typically has two upper hinge beams and two latch beams.

  Many systems that perform petal deflection have been proposed, but require a large force to actuate the petal's leading edge region and move the petal. These solutions also use mechanical components that create mechanical friction and wear.

US Patent Application Publication No. 2005/0198777 US Pat. No. 6,100,143

  It would be desirable to provide a petal actuation system that is lighter in weight and less subject to wear than mechanical actuators with comparable power, thus requiring less maintenance.

  The subject matter disclosed herein is directed to a petal actuation system where the principle of actuation is realized by a change in shape (ie, deformation) of the actuator rather than the movement of cooperating mechanical parts. Since these actuators have no rotating or sliding mechanical components, wear and associated maintenance is reduced. According to embodiments disclosed herein, a deformable actuator is a shape memory alloy that has been trained to change shape in a particular manner when energized (ie, heated). SMA). Each SMA actuator is shaped to act as a fairing that reduces aerodynamic drag. Using an SMA actuator, the flow control surface can be made a lighter design by restoring the nacelle hoop strength at the trailing edge. The design of the SMA actuator also improves system reliability because if an actuator system fails, the adjacent petals will remain in the last commanded position.

  According to some embodiments, the petal actuation system comprises two sets of circumferentially distributed unidirectional SMA actuators. One set can be heated to deflect the petal outward, and the other set can be heated to deflect the petal inward. One-way SMA actuators are arranged in pairs between adjacent petals. Each pair constitutes a respective first and second set of SMA actuators that act oppositely (ie, oppose). The opposing SMA actuator pair is mounted near the trailing edge of the petal. When the SMA actuator is mounted near the trailing edge of the nozzle, the force required to control the angular position of the flow surface is minimized.

  According to another embodiment, the petal actuation system comprises a set of circumferentially distributed two-way SMA actuators. (In this specification, the term “two-way SMA actuator” refers to an actuator with a shape memory alloy that has been trained to produce a two-way memory effect.) Each two-way SMA actuator is alternately heated and Once cooled, the petals can be deflected outward and inward (or alternatively inward and outward, respectively). Similar to one-way SMA actuators, two-way SMA actuators are placed between adjacent petals near the trailing edge.

  One aspect of the subject matter disclosed herein includes a support member having a curved shape and a first member connected to the support member such that the first and second petals can be displaced inward or outward, respectively. A first petal and a second petal that are separated from each other by a gap, a first part that spans the gap, and a first petal connected to the first part. And a body with a second portion and a third portion attached to the second petal, respectively, and a variable area fan nozzle. The first portion is made from a shape memory alloy having the characteristic of undergoing a first shape change when its temperature rises from below the transition temperature to above the transition temperature. The main body is arranged to deflect the first petal and the second petal when the first portion of the main body undergoes a first shape change. Preferably, the first portion of the body has a profile (eg, a V-shaped cross section) designed to minimize aerodynamic drag. In many cases where the variable area fan nozzle comprises a left fan nozzle assembly and a right fan nozzle assembly, each fan nozzle assembly can comprise the elements mentioned in this paragraph.

  According to one embodiment, the shape memory alloy can have the further feature that it undergoes a second shape change when its temperature drops from above the transition temperature to below the transition temperature. In this case, the body is deflected outwardly to deflect the first petal and the second petal when the first portion of the body receives one of the two shape changes, and the first part of the body When the part receives the other of the shape changes, it is displaced inward.

  According to another embodiment, instead of using a two-way shape memory alloy, the variable area fan nozzle is further coupled to a first portion spanning the gap and a first portion of the second body connected to the first petal. And a second body with a second portion and a third portion attached to the second petal, respectively. This embodiment may have the following additional properties: (a) The first portion of the second body is characterized by undergoing a second shape change when its temperature rises from below the transition temperature to above the transition temperature. (B) the second body is configured such that the first petal and the second petal are biased inward when the first portion of the second body undergoes a second shape change. (C) the first body deviates outwardly when the first portion of the first body undergoes a first shape change. It is arranged to let you.

  Another aspect of the presently disclosed subject matter is a method for changing an exit area of a nozzle, the temperature of each portion of the first plurality of elements being increased from below a transition temperature to above a transition temperature. Each part of the first plurality of elements is made from a shape memory alloy that changes shape while the temperature rises from below the transition temperature to above the transition temperature.

  According to a further aspect, the variable area fan nozzle includes a plurality of petals that can be displaced inward or outward simultaneously, and a plurality of first petal displacement actuators attached to the petals, wherein the first plurality of petals Each of the displacement actuators includes a shape memory alloy whose shape changes when its temperature rises from below the transition temperature to above the transition temperature, and the first plurality of petal displacement actuators whose petals are displaced due to the shape change. Prepare.

  According to one embodiment, the shape memory alloy also changes shape when its temperature drops from above the transition temperature to below the transition temperature. The petal is displaced in a certain direction when the shape of the petal displacement actuator is changed due to a temperature rise, and is displaced in the opposite direction when the shape of the petal displacement actuator is changed due to a temperature decrease.

  According to another embodiment, the variable area fan nozzle further comprises a second plurality of petal displacement actuators attached to the petals, each of the second plurality of petal displacement actuators having a temperature below the transition temperature. Shape memory alloys whose shape changes as the temperature rises above the transition temperature. Due to the shape change of the first plurality of petal displacement actuators, the petal is displaced in a certain direction, and due to the shape change of the second plurality of petal displacement actuators, the petal is displaced in the opposite direction.

  Yet another aspect is a plurality of petals connected with a sleeve or duct having a trailing edge lip region with a support member having a curved shape and each petal being deflected inward or outward, Adjacent petals separated from each other by a gap, and a plurality of petals and a plurality of deformable elements distributed in the gap, each of the deformable elements being heated to a temperature above the transition temperature A deformable element comprising a shape memory alloy that changes shape, a plurality of electric heaters thermally connected to the respective surfaces of the deformable element, and a program to control the supply of power to the electric heater Installed on an aircraft with an integrated computer system. The apparatus can further comprise one or more sensors that generate a position feedback signal representative of the current position of the petal. Thus, the computer system is programmed to provide an electrical pulse to the heater so that the shape of the deformable element changes or maintains, the number of pulses being the target position data representing the petal target position and position feedback. It changes according to the result of comparison with the position feedback data generated from the signal.

  Other aspects are disclosed and claimed below.

1 shows a partial isometric view of a typical aircraft turbofan engine having a variable area fan nozzle with a left side assembly and a right side assembly (only the left side assembly is shown). FIG. Displacement inward or outward alternately by changing the shape of one or the other of a pair of mutually deformable actuators disposed in a gap near the trailing edge of the petal according to one embodiment FIG. 6 shows an isometric view (from the top) of a pair of adjacent petals that can be made. The petals are shown in a position displaced outward (upper) and a position displaced inward (lower). Shows a pair of petals that deviate upward (ie, outward) when one of the deformable actuators that oppose each other expands (indicated by arrows A and B). It is a conceptual diagram. Shows a pair of petals that deviate downward (ie, inward) when the other of the pair of deformable actuators that oppose each other contracts (indicated by arrows C and D). It is a conceptual diagram. FIG. 3 shows an isometric view (from below) of the petal and deformable actuator depicted in FIG. Again, the petals are shown in an outwardly displaced position and an inwardly displaced position. Adjacent ones that can be alternately displaced inward or outward by heating one or the other of a pair of mutually deformable actuators disposed in a gap near the trailing edge of the petal according to a further embodiment FIG. 5 is an isometric view (from above) of a pair of petals. The broken line indicates the position of the petal cover (not shown). FIG. 3 is a block diagram that represents some of the components of a petal excursion system according to one embodiment.

  Reference will now be made to the drawings, in which like elements have the same reference numerals in the different drawings.

  Various embodiments applied to turbofan aircraft engine reverse thrust sleeves will now be described. However, the disclosed variable area fan nozzle system also applies to the trailing edge lip region of a fan duct that does not incorporate a reverse thrust sleeve.

  FIG. 1 shows a partial isometric view of a typical aircraft turbofan engine having a variable area fan nozzle with a left side assembly and a right side assembly (only the left side assembly is shown). A core engine nacelle surrounds a core engine (not shown). The turbofan engine includes a core flow of engine exhaust that exits the core flow nozzle 12 that forms the downstream end of the core engine nacelle, and a variable area fan nozzle 14 (on the right side assembly not shown) mounted at the downstream end or lip region of the reverse thrust sleeve 16. Thrust from both the fan flow that comes out of (including). The sleeve 16 overlaps at least a portion of the core engine nacelle. In general, the core flow is faster than the fan flow.

  According to one known implementation, the variable area fan nozzle 14 includes a number of hinged rigid petals 18 that change the fan flow through the fan duct when deflected inward or outward. It is configured. Optionally, the petal 18 can have a chevron (not shown) attached to its distal end (ie, the rear end). The petals 18 are arranged along the trailing edge lip of the reverse thrust sleeve 16. On the other hand, if the reverse thrust sleeve is a piece of sleeve (not shown in FIG. 1) that is axially translatable, the petal row extends from one side of the engine pylon to the opposite side of the fan duct. Will extend along most of. On the other hand (as shown in FIG. 1), the reverse thrust sleeve is an axially translatable half mounted on a rail secured to the upper (ie, hinge) beam 20 and the lower (ie, latch) beam 22. In the case of two cowls, the petal train consists of two sets of petals attached to each half cowl. Each set of petals comprises eight petals, which are distributed circumferentially along a curve extending from each upper beam to each lower beam on each side of the engine.

  According to the embodiment shown in FIG. 1, the forward end of the petal 18 is pivotally connected to the bulkhead 26 by respective hinges. The bulkhead 26 has a circular arc shape centered on an axis. Optionally, the hinge can be a flexible (ie, living) hinge made from a composite or metal material. The end of the arc-shaped bulkhead 26 is supported by the hinge beam 20 and the latch beam 22. A control system is configured to control an actuation system (not shown in FIG. 1). The operating system deflects the petal 18 inward from the rated position under cruise flight conditions to maximize fuel efficiency. When the actuation system is reversed, the petals return to their rated positions.

  For each set of petals, adjacent petals 18 are separated by a triangular or trapezoidal gap or space, each of which is occupied by a respective elastomeric seal that is connected to the adjacent petal. Secured to eliminate leaks. In FIG. 1, the elastomer seals are covered by respective gap covers 10. Each gap cover 10 is attached to the left edge of each petal 18 and is not attached to an adjacent petal so that when the petal moves inward, the gap narrows and when it moves outward. The gap can be widened.

  Many types of actuation systems have been proposed for controlling the petal position of variable area fan nozzles. In the petal actuation system disclosed herein, the principle of actuation is realized by a change in shape (ie, deformation) of the petal excursion actuator rather than movement of cooperating mechanical parts. According to embodiments disclosed herein, a deformable actuator includes a shape memory alloy that has been trained to change shape in a particular manner upon heating. Each SMA actuator is shaped to act as a fairing to reduce aerodynamic drag.

  According to one embodiment shown in FIGS. 2-5, the petal actuation system comprises two sets of circumferentially distributed unidirectional SMA actuators. One set can be heated to deflect the petal outward, and the other set can be heated to deflect the petal inward. One-way SMA actuators are located in pairs between adjacent petals. Each pair constitutes a respective first and second set of SMA actuators acting in opposition (ie, opposing each other). The opposing SMA actuator pair is mounted near the trailing edge of the petal. When the SMA actuator is mounted near the trailing edge of the nozzle, the force required to control the angular position of the flow surface is minimized.

  FIG. 2 shows an isometric view (from above) of a pair of adjacent petals 18a and 18b. These petals are either inwardly deformed by changing the shape of one or the other of a pair of mutually deformable actuators 2 and 4 disposed in a gap near the trailing edge of the petal according to one embodiment. It can be displaced to the outside alternately. The petals are shown in a position displaced outward (upper) and a position displaced inward (lower).

  According to the embodiment shown in FIG. 2, the SMA actuator 2 is configured and trained to change shape so that the petals 18a and 18b are deflected outward, and the SMA actuator 4 includes the petals 18a and 18b. The configuration and the training process are performed so that the shape changes so as to deviate 18b inward. Due to the shape change, an actuating force for deflecting the petal is generated. As can be seen in FIG. 2, petals 18a and 18b are separated by a gap. The SMA actuators 2 and 4 protrude through the gap, and the front edge of the SMA actuator 2 is located adjacent to the rear edge of the SMA actuator 4. The trailing edge of the SMA actuator can be aligned with the trailing edges of petals 18a and 18b. In the implementation shown in FIG. 2, the remainder of the gap is occupied by the elastomer seal 24. Alternatively, the elastomeric seal can extend under the SMA actuators 2 and 4 to the trailing edges of the petals 18a and 18b as shown in FIG. 6 (described in detail later).

  The principle of operation of the SMA actuators 2 and 4 is shown in FIGS. FIG. 3 shows the petals 18a and 18b being displaced upward (ie, outward) when the SMA actuator 2 is expanded (indicated by arrows A and B). FIG. 4 shows the petals 18a and 18b being displaced downward (ie, inward) when the SMA actuator 4 contracts (indicated by arrows C and D).

  As shown in FIG. 3, the SMA actuator 2 includes an active portion 2a that spans the gap between the petals 18a and 18b, a first flange 2b that is connected to the active portion 2a and attached to the petal 18b, and an active portion 2a. And a second flange 2c attached to the petal 18a. The active portion 2a is made of a shape memory alloy, and the shape memory alloy is characterized in that it undergoes a first shape change when its temperature rises from below the transition temperature to above the transition temperature. The SMA actuator 2 is arranged so as to deviate the petals 18a and 18b outward when the active portion 2a undergoes the first shape change. Preferably, the flanges 2b and 2c of the SMA actuator 2 are made of a material that is not susceptible to heat-induced shape changes. For example, the flanges 2b and 2c can be made from a shape memory alloy that has not been trained to change shape at the transition temperatures described above.

  As shown in FIG. 4, the SMA actuator 4 also includes an active portion 4a that spans the gap between the petals 18a and 18b, a first flange 4b that is connected to the active portion 4a and attached to the petal 18b, It is a main body provided with the 2nd flange 4c connected with the part 4a and attached to the petal 18a. The active portion 4a is made of a shape memory alloy and has a feature that it undergoes a second shape change when its temperature rises from below the transition temperature to above the transition temperature. The SMA actuator 4 is arranged to deflect the petals 18a, 18b inward when the active portion 4a undergoes the second shape change. Preferably, the flanges 4b and 4c of the SMA actuator 4 are made of a material that is not susceptible to heat-induced shape changes. For example, the flanges 4b and 4c can be made from a shape memory alloy that has not been trained to change shape at the transition temperatures described above.

  Each active portion 2a and 4a of SMA actuators 2 and 4 can be made from different shape memory alloys, in which case the respective transition temperatures mentioned in the previous two paragraphs may be different. Preferably, each active portion 2a and 4a each has a profile (eg, a V-shaped cross section) designed to minimize aerodynamic drag.

  According to one embodiment, the flanges 2b and 2c of the SMA actuator 2 and the flanges 4b and 4c of the SMA actuator 4 are attached to respective peripheral portions of the inner surfaces of the petals 18a and 18b, as shown in FIG. The elastomer seal 24 may also include flanges 24a and 24b for attachment of respective peripheral portions of the inner surfaces of the petals 18a and 18b.

  It should be understood that the shape memory alloy incorporated in the actuator described above has been trained according to the desired restraining motion, and that restraining motion varies depending on the relative motion of the connected structure. Shape memory alloys are trained to different degrees of motion based on the design of different “trainers” (mechanical mechanisms used to train shape memory alloys to maintain their memory shape). Can be processed.

  The two main types of shape memory alloys are copper-aluminum-nickel and nickel-titanium (Nitinol) alloys, but shape memory alloys can also be created by alloying zinc, copper, gold, and iron. it can. In various embodiments, the actuator can include nitinol, but other various shape memory alloys of copper, zinc, aluminum, nickel, titanium, palladium, and / or other materials can also be used. The transition temperature of the shape memory alloy is very sensitive to the composition of the alloy and can be selected by slightly changing the composition ratio. The material selection for the rod can be made based on various design considerations such as operating temperature range, desired transition temperature, desired transition time, combinations thereof, and the like.

  More specifically, in some embodiments, the actuator may be formed from “Nitinol 55”, a two-component form of Nitinol with 55 wt% nickel. It should be understood that this embodiment is illustrative and should not be construed as limiting in any way. For example, in some contemplated embodiments, the actuator can be formed from two or more alloys, at least one of the alloys being a shape memory alloy, and at least one of the alloys being steel, brass It is not a shape memory alloy. Thus, the actuator is formed from a combination of materials and / or alloys such that various portions or portions of the actuator are responsive to transitions at different transition temperatures and / or at different times relative to other portions or portions of the actuator. It will be understood that it can. For example, the active portion of each actuator can be formed from a shape memory alloy and the passive flange is formed from an alloy that is not a shape memory alloy.

  FIG. 6 illustrates that inward or outward by heating one or the other of a pair of opposing one-way SMA actuators 2 and 4 disposed in a gap near the trailing edge of the petal according to a further embodiment. An isometric view (from the top) of a pair of adjacent petals 18a and 18b that can be displaced alternately is presented. A broken line displays a part of a petal cover (not shown). In this embodiment, respective electric heaters are thermally connected to the surfaces of the one-way SMA actuators 2 and 4. If the SMA actuator 2 is heated and the SMA actuator 4 is not heated, the actuation force caused by the deformation of the actuator 2 should be greater than the deformation resistance of the actuator 4 and vice versa.

  FIG. 6 shows respective foil heaters 34 and 36 attached to respective surfaces of the active portions of SMA actuators 2 and 4. Each foil heater includes a conductive foil that is etched to form a serpentine pattern. During manufacture, the foil is attached to a backing material and then etched into the desired pattern. The etched foil is then overlaid on a dielectric matrix (eg, silicon), connections (eg, conductive foil tabs or wires) are directed out of the matrix, and then the matrix is cured (if necessary) Remove the backing material). The foil heater 34 is coupled to the visible surface (in FIG. 6) of the active portion of the SMA actuator 2, thereby being thermally connected and coupled to a power source (not shown) by a pair of conductors 38. And a meandering conductor. Another foil heater (not visible in FIG. 6) can be coupled to the surface on the other side of the active portion of the SMA actuator 2. Similarly, the foil heater 36 is coupled to the visible surface of the active portion of the SMA actuator 4 so that it is thermally connected and serpentine coupled to a power source (not shown) by a pair of conductors 40. A conductor is provided. Another foil heater (not visible in FIG. 6) can be coupled to the surface on the other side of the active portion of the SMA actuator 4. As current flows through the serpentine conductors of the heating coil of the foil heater, the shape memory alloy in the active part of the actuator is heated.

  Figures 2-6 depict a petal excursion actuation system using a pair of one-way SMA actuators that oppose each other. In these embodiments, the SMA material is heated to change its martensite shape (ie, its shape when its crystalline state is martensite) to its austenite shape (ie, its shape when its crystalline state is austenite). ), Thereby generating an actuating force that deflects the VAFN petal. Each one-way SMA actuator changes from its martensite shape to its austenite shape when fully heated, and the shape change stops when the heating element is turned off, then the other one-way SMA actuator Changes from its martensite shape to its austenite shape (although the unheated actuator provides a resistive force that resists the actuation force produced by the heated actuator).

  According to the above-described embodiment, if one of the two sets of SMA actuators facing each other is heated and the other is not heated, the throat area of the variable area fan nozzle is reduced, and one of the two sets of SMA actuators facing each other is reduced. If one is not heated and the other is heated, the throat area increases. Fan nozzle throat area can reduce the area (compared to the rated area during cruising) to help fuel consumption during a certain part of the flight service, or increase the area to reduce noise Can contribute to the improvement of fan operability.

  In general, shape memory alloys are metallic alloys that have significantly different phases on both sides of the transition temperature. A first physical state is reached when the shape memory alloy is below its transition temperature, and a second physical state is reached when its transition temperature is exceeded. Some shape memory alloy materials can be trained to have a first shape in a cooler first state and a second shape in a warmer second state. The trained two-way shape memory alloy is forced to assume a second shape when heated above the transition temperature and then gradually to the first shape when cooled below the transition temperature, if not limited. You can go back.

  According to an alternative embodiment, a set of two-way SMA actuators can be used instead of a paired one-way actuator. In order to allow reversible operation in two directions, the active portion of each SMA actuator has a two-way shape with a two-way shape memory alloy thermally circulated between a first temperature and a second temperature. When changing the memory alloy from the first state to the second state, 2 adapted to the transition between the first training processed shape and the second training processed shape without being subjected to external load. It can be made from a directional shape memory alloy. A method of making a two-way SMA element is disclosed in US Patent Application Publication No. 2005/0198777, the contents of which are incorporated herein in their entirety.

  In an exemplary embodiment, the first state is the austenitic state of the two-way shape memory alloy and the second state is the martensitic state of the two-way shape memory alloy. When thermally activated or heated, the two-way shape memory alloy begins to enter the austenite state at its austenite start temperature (the temperature at which transformation from martensite to austenite begins during heating). During such a transformation from martensite to austenite, the two-way SMA actuator deforms towards the first training or austenite shape. When the heating is continued, the two-way shape memory alloy finally completes the transformation from martensite to austenite at the austenite finish temperature (the temperature at which transformation from martensite to austenite is completed during heating). The austenite start and finish temperatures and the martensite to austenite transformation rate depend on the specific application and its thermal environment, the composition of the shape memory alloy material used, and / or the amount of thermal energy applied to the two-way SMA actuator. It should be understood that this can be changed depending on the ratio.

  During cooling, the two-way shape memory alloy begins to enter the martensite state at its martensite start temperature (the temperature at which transformation from austenite to martensite begins during cooling). During such austenite to martensite transformation, the two-way SMA actuator deforms toward the second trained or martensitic shape. When cooling continues, the two-way shape memory alloy finally completes the transformation from austenite to martensite at its martensite finish temperature (the temperature at which transformation from austenite to martensite is completed during cooling). The martensite start and end temperatures and the rate of transformation from austenite to martensite depend on the specific application and its thermal environment, the composition of the specific SMA material used and / or the cooling or heat transfer by the two-way SMA actuator. It should be understood that it can vary depending on the amount and speed.

  Referring again to FIGS. 3 and 4, a two-way SMA actuator can be used in place of the pair of one-way SMA actuators 2 and 4, and the trailing edge of the two-way SMA actuator is aligned with the trailing edge of petals 18a and 18b. Is done. The two-way SMA actuator can have the same profile as the one-way actuator depicted in FIGS. According to one embodiment, the shape memory alloys of the two-way actuator move (i.e., expand) the actuator flanges alternately away from each other during heating and move toward each other during cooling ( That is, the training process can be performed so as to contract. According to another embodiment, the shape memory alloy of a two-way actuator can be trained so that the actuator flanges move alternately toward one another during heating and away from one another during cooling.

  Cooling the two-way shape memory alloy can include passive cooling, active cooling, combinations thereof, and the like. In one embodiment, the two-way shape memory alloy is passively cooled by heat exchange with its surrounding environment (eg, structure, ambient atmosphere, etc.) when power to the heating device is interrupted. Alternatively or additionally, the two-way shape memory alloy can be actively cooled, for example if a faster transformation to martensite state and martensite shape is desired. As an example, a two-way shape memory alloy can be actively cooled by circulating coolant through a two-way SMA actuator.

  As a further example, a two-way shape memory alloy can be actively cooled by supplying power to a thermoelectric element, one side of which is thermally connected to the shape memory alloy. The thermoelectric element is characterized in that heat flows from one side of the thermoelectric element to the other side. Accordingly, the shape memory alloy can be cooled when thermally connected to the cooled side of the thermoelectric element. Advanced thermoelectric elements are disclosed in US Pat. No. 6,100,463, the contents of which are incorporated herein in their entirety.

  The state of the SMA actuator can be automatically controlled in response to flight conditions. FIG. 7 illustrates a system architecture for controlling the deflection of a variable area fan nozzle petal according to one embodiment. The angular position of the plurality of VAFN petals 18 changes according to the temperature of the shape memory alloy of the active portion of the plurality of VAFN actuators 50, and the temperature depends on the amount of heat transferred to the shape memory alloy of the actuator by the plurality of electric heaters 48. Accordingly, the electric heater 48 is thermally connected to the actuator (as indicated by the horizontal dashed line separating the actuator 50 and the heater 48 in FIG. 7).

  The amount of heat supplied by the electric heater is controlled by an onboard VAFN control unit 52 which is a closed loop control system. The VAFN control unit 52 may be implemented as part of a computer system (eg, a central computer or processor), a subsystem that computer processes a dedicated module that controls petal excursions, and the like. Optionally, the excursion of the petal 18 can be measured by a position feedback system 58 (eg, a fiber optic system), which in the VAFN petal 18 outputs a signal representative of those measurements. A sensor mounted on or near it. The VAFN control unit 52 receives inputs from the full-function digital engine control unit 54 and the position feedback system 58 and then continuously adjusts the degree of petal excursion via the actuation system, thereby receiving the received petals. The fan nozzle throat area is adjusted based on the position information.

  For each VAFN actuator, the position of the SMA actuator varies depending on the amount of heat provided to the associated heating element. The amount of heat is controlled by the VAFN control unit 52. The VAFN control unit 52 receives power (eg, 115 VAC) from the aircraft power supply 56 and then provides power pulses or power bursts to the electric heater 48 to maintain the actuator in a particular position. The VAFN control unit 52 is programmed to send a specific number of pulses to each heater to deform each actuator to its respective shape corresponding to the target petal position (not necessarily for each heater. Not necessarily the same number). The VAFN control unit 52 then receives a position feedback signal representative of the actual (ie, current) petal position. In response to these position feedback signals, the VAFN control unit 52 provides current pulses in effect to maintain each heater at a particular temperature and subsequently maintain each petal at the target position.

  In order to increase the flow area at the exit of the variable area fan nozzle when a pair of one-way SMA actuators is used, the first one-way SMA actuator is heated and the second one-way SMA actuator is not heated. In order to reduce the flow area at the outlet, the first one-way SMA actuator is heated and the second one-way SMA actuator is not heated. To achieve any target outlet flow area between the maximum and minimum outlet flow areas, the current outlet flow area is targeted based on the position feedback signal during the open or closed cycle. The heat supply to the heated actuator is shut off by the VAFN control unit when it is calculated to be within a specified threshold of the outlet flow area of Additional power pulses are provided as needed to maintain the current outlet flow area.

  The SMA actuator can be heated by means other than an electric heater. It is known to supply pressurized hot air to an environmental control system using the compressor portion of a gas turbine engine. The pressurized air is usually referred to as “bleed” and is withdrawn from the bleed ports located at various stages of compression in the multistage compressor portion of the engine. According to an alternative embodiment of the petal excursion system, the SMA actuator can be heated by releasing a valve that diverts some bleed air to flow over the surface of the SMA actuator.

  Exemplary and non-exclusive subject matter examples according to this disclosure are set forth in the paragraphs listed below.

A1.
A support member having a curved shape;
A first petal and a second petal connected to the support member so that the first petal and the second petal can be displaced inward or outward, respectively, and separated from each other by a gap And a second petal,
A first portion that spans the gap, and a second portion and a third portion that are connected to the first portion and attached to the first petal and the second petal, respectively. The body is made of a shape memory alloy characterized by undergoing a first shape change when its temperature rises from below the transition temperature to above the transition temperature. The first body is arranged to deflect the first petal and the second petal when the first portion of the first body is subjected to the first shape change. A variable area fan nozzle.

A2.
The variable area fan nozzle according to paragraph A1, wherein when the first portion of the first body undergoes the first shape change, the first petal and the second petal are offset outward.

A3.
The variable area fan nozzle according to paragraph A1, wherein when the first portion of the first body undergoes the first shape change, the first petal and the second petal are displaced inward.

A4.
The variable area fan nozzle according to paragraphs A1 to A3, wherein the first portion of the first body has a V-shaped cross section.

A5.
A second portion comprising a first portion spanning the gap, and a second portion and a third portion connected to the first portion and attached to the first petal and the second petal, respectively. The main body is further provided,
The first portion of the second body is made of a shape memory alloy characterized by undergoing a second shape change when its temperature rises from below the transition temperature to above the transition temperature;
The second body is arranged to deflect the first petal and the second petal inward when the first part of the second body is subjected to the second shape change. And
The first body is arranged to deflect the first petal and the second petal outward when the first portion of the first body undergoes the first shape change. Yes,
Variable area fan nozzle according to paragraphs A1 to A4.

A6.
The shape memory alloy has the further feature that it undergoes a second shape change when its temperature drops from above the transition temperature to below the transition temperature, and the first body comprises the first body of the first body. When one portion receives one of the first shape change and the second shape change, the first petal and the second petal are displaced outwardly, and the first body of the first body The variable area fan nozzle according to paragraphs A1 to A5, wherein when one portion receives the other of the first shape change and the second shape change, the portion is displaced inward.

A7.
The variable area fan nozzle of paragraphs A1 through A6, further comprising means for heating the first portion of the first body.

A8.
The variable area fan nozzle of paragraphs A1 through A7, further comprising a heating coil thermally connected to a surface of the first portion of the first body.

A9.
The variable area fan nozzle of paragraphs A1 through A8, further comprising a seal made of an elastomeric material, wherein the seal comprises a portion spanning the gap between the first petal and the second petal.

A10.
A left fan nozzle assembly and a right fan nozzle assembly, each of the left fan nozzle assembly and the right fan nozzle assembly each having a curved shape, and each first member disposed as described in A1. The variable area fan nozzle according to paragraphs A1 to A9, comprising: a petal and a second petal, and a respective first body whose shape changes as described in A1.

A11.
A method for changing an exit area of a nozzle, the method comprising increasing a temperature of a respective portion of a first plurality of elements from below a transition temperature to above a transition temperature, and each of the first plurality of elements The method wherein the portion is made from a shape memory alloy that changes shape while the temperature rises from below the transition temperature to above the transition temperature.

A12.
Further comprising increasing the temperature of each portion of the second plurality of elements from below the transition temperature to above the transition temperature, wherein the respective portion of the second plurality of elements is from below the transition temperature to the transition temperature. Made from a shape memory alloy that changes shape while the temperature rises to above, and the outlet area increases when the shape of each of the portions of the first plurality of elements changes, the second plurality of The method of paragraph A11, wherein the method decreases as the shape of the respective portion of the element changes.

A13.
Further comprising reducing the temperature of the respective portion of the first plurality of elements from above the transition temperature to less than the transition temperature, the shape memory alloy of the respective portion of the first plurality of elements also comprising: The shape changes while the temperature decreases from above the transition temperature to less than the transition temperature, and the exit area increases when the shape of the respective portion of the first plurality of elements changes as a result of the temperature increase, The method of paragraph A11 or A12, wherein the method decreases as the shape of the respective portion of the first plurality of elements changes as a result of a temperature drop.

A14.
Further comprising reducing the temperature of the respective portion of the first plurality of elements from above the transition temperature to less than the transition temperature, the shape memory alloy of the respective portion of the first plurality of elements also comprising: The shape changes while the temperature drops from above the transition temperature to less than the transition temperature, and the outlet area decreases when the shape of the respective portion of the first plurality of elements changes due to temperature rise, The method of paragraph A11, wherein the method increases when the shape of the respective portion of the first plurality of elements changes due to the decrease.

A15.
Multiple petals that can be displaced inward or outward at once,
A first plurality of petal displacement actuators attached to the petal, wherein each of the first plurality of petal displacement actuators changes its shape when its temperature rises from below the transition temperature to above the transition temperature. A variable area fan nozzle comprising a first plurality of petal displacement actuators including a memory alloy, wherein the petals are displaced by a shape change of the first plurality of petal displacement actuators.

A16.
A second plurality of petal deflection actuators attached to the petal;
Each of the second plurality of petal displacement actuators includes a shape memory alloy that changes its shape when its temperature rises from below the transition temperature to more than the transition temperature, and the shape change of the first plurality of petal displacement actuators The variable area fan nozzle of paragraph A15, wherein the petal is deflected outward and the petal is deflected inward due to a shape change of the second plurality of petal displacement actuators.

A17.
The shape memory alloy also changes shape when its temperature drops from above the transition temperature to below the transition temperature, and the petal changes shape of the first plurality of petal displacement actuators as a result of the temperature increase. The variable area fan nozzle of paragraph A15 or A16, wherein the petal is displaced outward and the petal is displaced inward as the first plurality of petal displacement actuators change shape as a result of a temperature drop.

A18.
The shape memory alloy also changes shape in which its temperature decreases from above the transition temperature to below the transition temperature, and the petal changes shape as a result of the temperature increase. The variable area fan nozzle of paragraph A15, wherein the petal is displaced inward and the petal is displaced outward as the first plurality of petal displacement actuators change shape as a result of a temperature drop.

A19.
A sleeve or duct having a trailing edge lip region with a support member having a curved shape;
A plurality of petals connected to the support member such that each petal can be deflected inward or outward, wherein adjacent petals are separated from each other by respective gaps;
A plurality of deformable elements distributed in the gap, each including a shape memory alloy that changes shape when heated to a temperature above the transition temperature;
A plurality of electric heaters thermally connected to respective surfaces of the deformable element;
And a computer system programmed to control the supply of power to the electric heater.

A20.
One or more sensors for generating a position feedback signal representative of the current position of the petal, wherein the computer system is configured to electrically connect the electric heater to change or maintain the shape of the deformable element. Paragraph A19, programmed to provide pulses, wherein the number of pulses varies depending on the result of a comparison between target position data representing the petal target position and position feedback data generated from the position feedback signal. Equipment. Although variable area fan nozzles have been described in connection with various embodiments, various modifications can be made without departing from the scope of the claims set forth below, and equivalents may be substituted for the elements Those skilled in the art will appreciate that this is possible. In addition, many modifications may be made to adapt a teaching of this specification to a particular situation without departing from the scope of the claims.

  In the claims, the term “computer system” should be broadly interpreted as encompassing a system having at least one computer, processor, or computing module, and a plurality of computers, processors, or in communication over a network or bus. It can have a computing module.

2 SMA actuator 2a Active part 2b 1st flange 2c 2nd flange 4 SMA actuator 4a Active part 4b 1st flange 4c 2nd flange 10 Crevice cover 12 Core flow nozzle 14 Variable area fan nozzle 16 Reverse thrust sleeve 18 Petal , Hinged petal, rigid petal, VAFN petal 18a petal 18b petal 20 hinge beam 22 latch beam 24 elastomer seal 24a flange 24b flange 26 bulkhead 34 foil heater 36 foil heater 40 pair of conductors 48 electric heater 50 VAFN actuator 52 VAFN Control unit 54 Full-function digital engine control unit 56 Aircraft power supply 58 Position feedback system

Claims (14)

A support member having a curved shape;
A first petal and the second petal, which are adjacently disposed along the curved shape of the support member, such that the first petal and the second petal can biased inward or outward, respectively The first petal and the second petal connected to the support member and separated from each other by a gap;
A first portion that spans the gap, and a second portion and a third portion that are connected to the first portion and attached to the first petal and the second petal, respectively. The body is made of a shape memory alloy characterized by undergoing a first shape change when its temperature rises from below the transition temperature to above the transition temperature. The main body is disposed so as to deviate the first petal and the second petal when the first portion of the first main body is subjected to the first shape change . A variable area fan nozzle comprising a first body, wherein the first portion has a V-shaped cross section .   The variable area fan nozzle according to claim 1, wherein when the first portion of the first body is subjected to the first shape change, the first petal and the second petal are displaced outward.   The variable area fan nozzle according to claim 1, wherein when the first portion of the first body is subjected to the first shape change, the first petal and the second petal are displaced inward. A second portion comprising a first portion spanning the gap, and a second portion and a third portion connected to the first portion and attached to the first petal and the second petal, respectively. The main body is further provided,
The first portion of the second body is made of a shape memory alloy characterized by undergoing a second shape change when its temperature rises from below the transition temperature to above the transition temperature;
The second body is arranged to deflect the first petal and the second petal inward when the first part of the second body is subjected to the second shape change. And
The first body is arranged to deflect the first petal and the second petal outward when the first portion of the first body undergoes the first shape change. Yes,
The variable area fan nozzle according to any one of claims 1 to 3 .   The shape memory alloy has the further feature that it undergoes a second shape change when its temperature drops from above the transition temperature to below the transition temperature, and the first body comprises the first body of the first body. When one portion receives one of the first shape change and the second shape change, the first petal and the second petal are displaced outwardly, and the first body of the first body 5. The variable area fan nozzle according to claim 1, wherein when one portion receives the other of the first shape change and the second shape change, the portion is displaced inwardly. 6. 6. The variable area fan nozzle according to any one of claims 1 to 5 , further comprising means for heating the first portion of the first body. The variable area fan nozzle according to any one of claims 1 to 6 , further comprising a heating coil thermally connected to a surface of the first portion of the first body. The variable area according to any one of claims 1 to 7 , further comprising a seal made of an elastomeric material, the seal comprising a portion spanning the gap between the first petal and the second petal. Fan nozzle. 9. A left side fan nozzle assembly and a right side fan nozzle assembly, each of the left side fan nozzle assembly and the right side fan nozzle assembly each having a curved shape, and according to any one of claims 1 to 8 . provided so that each of the first petal and the second petal disposed so, and each of the first body that changes shape as claimed in any one of claims 1 to 8, claim 1 The variable area fan nozzle as described in any one of 1 to 8 . A method for changing the exit area of the variable area fan nozzle according to any one of claims 1 to 9, wherein the temperature of each portion of the first plurality of elements is increased from below the transition temperature to above the transition temperature. And is made from a shape memory alloy in which the shape of the respective portion of the first plurality of elements changes as the temperature rises from below the transition temperature to above the transition temperature. Further comprising increasing the temperature of each portion of the second plurality of elements from below the transition temperature to above the transition temperature, wherein the respective portion of the second plurality of elements is from below the transition temperature to the transition temperature. Made from a shape memory alloy that changes shape while the temperature rises to above, and the outlet area increases when the shape of each of the portions of the first plurality of elements changes, the second plurality of The method of claim 10 , wherein the method decreases as the shape of the respective portion of the element changes. Further comprising reducing the temperature of the respective portion of the first plurality of elements from above the transition temperature to less than the transition temperature, the shape memory alloy of the respective portion of the first plurality of elements also comprising: The shape changes while the temperature decreases from above the transition temperature to less than the transition temperature, and the exit area increases when the shape of the respective portion of the first plurality of elements changes as a result of the temperature increase, The method of claim 10 , wherein the method decreases as the shape of the respective portion of the first plurality of elements changes as a result of a temperature drop. Further comprising reducing the temperature of the respective portion of the first plurality of elements from above the transition temperature to less than the transition temperature, the shape memory alloy of the respective portion of the first plurality of elements also comprising: The shape changes while the temperature drops from above the transition temperature to less than the transition temperature, and the outlet area decreases when the shape of the respective portion of the first plurality of elements changes due to temperature rise, The method of claim 10 , wherein the increase increases as the shape of the respective portion of the first plurality of elements changes due to the decrease. The variable area fan nozzle according to any one of claims 1 to 5 , 8 and 9 ,
A plurality of electric heaters;
The system which controls the deviation of the petal of a variable area fan nozzle provided with a VAFN control unit.

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